xref: /titanic_52/usr/src/cmd/cmd-inet/sbin/dhcpagent/agent.c (revision d2d5cf7c5d909b74a88d499283e24750a9a52c5d)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #include <sys/types.h>
27 #include <stdlib.h>
28 #include <errno.h>
29 #include <locale.h>
30 #include <string.h>
31 #include <unistd.h>
32 #include <signal.h>
33 #include <stdio.h>
34 #include <stdio_ext.h>
35 #include <dhcp_hostconf.h>
36 #include <dhcpagent_ipc.h>
37 #include <dhcpagent_util.h>
38 #include <dhcpmsg.h>
39 #include <netinet/dhcp.h>
40 #include <net/route.h>
41 #include <sys/sockio.h>
42 #include <sys/stat.h>
43 #include <stropts.h>
44 #include <fcntl.h>
45 #include <sys/scsi/adapters/iscsi_if.h>
46 
47 #include "async.h"
48 #include "agent.h"
49 #include "script_handler.h"
50 #include "util.h"
51 #include "class_id.h"
52 #include "states.h"
53 #include "packet.h"
54 #include "interface.h"
55 #include "defaults.h"
56 
57 #ifndef	TEXT_DOMAIN
58 #define	TEXT_DOMAIN	"SYS_TEST"
59 #endif
60 
61 iu_timer_id_t		inactivity_id;
62 int			class_id_len = 0;
63 char			*class_id;
64 iu_eh_t			*eh;
65 iu_tq_t			*tq;
66 pid_t			grandparent;
67 int			rtsock_fd;
68 
69 static boolean_t	shutdown_started = B_FALSE;
70 static boolean_t	do_adopt = B_FALSE;
71 static unsigned int	debug_level = 0;
72 static iu_eh_callback_t	accept_event, ipc_event, rtsock_event;
73 
74 /*
75  * The ipc_cmd_allowed[] table indicates which IPC commands are allowed in
76  * which states; a non-zero value indicates the command is permitted.
77  *
78  * START is permitted if the state machine is fresh, or if we are in the
79  * process of trying to obtain a lease (as a convenience to save the
80  * administrator from having to do an explicit DROP).  EXTEND, RELEASE, and
81  * GET_TAG require a lease to be obtained in order to make sense.  INFORM is
82  * permitted if the interface is fresh or has an INFORM in progress or
83  * previously done on it -- otherwise a DROP or RELEASE is first required.
84  * PING and STATUS always make sense and thus are always permitted, as is DROP
85  * in order to permit the administrator to always bail out.
86  */
87 static int ipc_cmd_allowed[DHCP_NSTATES][DHCP_NIPC] = {
88 	/*			  D  E	P  R  S	 S  I  G */
89 	/*			  R  X	I  E  T	 T  N  E */
90 	/*			  O  T	N  L  A	 A  F  T */
91 	/*			  P  E	G  E  R	 T  O  _ */
92 	/*			  .  N  .  A  T  U  R  T */
93 	/*			  .  D	.  S  .  S  M  A */
94 	/*			  .  .  .  E  .  .  .  G */
95 	/* INIT		*/	{ 1, 0, 1, 0, 1, 1, 1, 0 },
96 	/* SELECTING	*/	{ 1, 0, 1, 0, 1, 1, 0, 0 },
97 	/* REQUESTING	*/	{ 1, 0, 1, 0, 1, 1, 0, 0 },
98 	/* PRE_BOUND	*/	{ 1, 1, 1, 1, 0, 1, 0, 1 },
99 	/* BOUND	*/	{ 1, 1, 1, 1, 0, 1, 0, 1 },
100 	/* RENEWING	*/	{ 1, 1, 1, 1, 0, 1, 0, 1 },
101 	/* REBINDING	*/	{ 1, 1, 1, 1, 0, 1, 0, 1 },
102 	/* INFORMATION  */	{ 1, 0, 1, 0, 1, 1, 1, 1 },
103 	/* INIT_REBOOT  */	{ 1, 0, 1, 1, 1, 1, 0, 0 },
104 	/* ADOPTING	*/	{ 1, 0, 1, 1, 0, 1, 0, 0 },
105 	/* INFORM_SENT  */	{ 1, 0, 1, 0, 1, 1, 1, 0 },
106 	/* DECLINING	*/	{ 1, 1, 1, 1, 0, 1, 0, 1 },
107 	/* RELEASING	*/	{ 1, 0, 1, 0, 0, 1, 0, 1 },
108 };
109 
110 #define	CMD_ISPRIV	0x1	/* Command requires privileges */
111 #define	CMD_CREATE	0x2	/* Command creates an interface */
112 #define	CMD_BOOTP	0x4	/* Command is valid with BOOTP */
113 #define	CMD_IMMED	0x8	/* Reply is immediate (no BUSY state) */
114 
115 static uint_t ipc_cmd_flags[DHCP_NIPC] = {
116 	/* DHCP_DROP */		CMD_ISPRIV|CMD_BOOTP,
117 	/* DHCP_EXTEND */	CMD_ISPRIV,
118 	/* DHCP_PING */		CMD_BOOTP|CMD_IMMED,
119 	/* DHCP_RELEASE */	CMD_ISPRIV,
120 	/* DHCP_START */	CMD_CREATE|CMD_ISPRIV|CMD_BOOTP,
121 	/* DHCP_STATUS */	CMD_BOOTP|CMD_IMMED,
122 	/* DHCP_INFORM */	CMD_CREATE|CMD_ISPRIV,
123 	/* DHCP_GET_TAG */	CMD_BOOTP|CMD_IMMED
124 };
125 
126 static boolean_t
127 is_iscsi_active(void);
128 
129 int
130 main(int argc, char **argv)
131 {
132 	boolean_t	is_daemon  = B_TRUE;
133 	boolean_t	is_verbose;
134 	int		ipc_fd;
135 	int		c;
136 	struct rlimit	rl;
137 
138 	debug_level = df_get_int("", B_FALSE, DF_DEBUG_LEVEL);
139 	is_verbose = df_get_bool("", B_FALSE, DF_VERBOSE);
140 
141 	/*
142 	 * -l is ignored for compatibility with old agent.
143 	 */
144 
145 	while ((c = getopt(argc, argv, "vd:l:fa")) != EOF) {
146 
147 		switch (c) {
148 
149 		case 'a':
150 			do_adopt = B_TRUE;
151 			grandparent = getpid();
152 			break;
153 
154 		case 'd':
155 			debug_level = strtoul(optarg, NULL, 0);
156 			break;
157 
158 		case 'f':
159 			is_daemon = B_FALSE;
160 			break;
161 
162 		case 'v':
163 			is_verbose = B_TRUE;
164 			break;
165 
166 		case '?':
167 			(void) fprintf(stderr, "usage: %s [-a] [-d n] [-f] [-v]"
168 			    "\n", argv[0]);
169 			return (EXIT_FAILURE);
170 
171 		default:
172 			break;
173 		}
174 	}
175 
176 	(void) setlocale(LC_ALL, "");
177 	(void) textdomain(TEXT_DOMAIN);
178 
179 	if (geteuid() != 0) {
180 		dhcpmsg_init(argv[0], B_FALSE, is_verbose, debug_level);
181 		dhcpmsg(MSG_ERROR, "must be super-user");
182 		dhcpmsg_fini();
183 		return (EXIT_FAILURE);
184 	}
185 
186 	if (is_daemon && daemonize() == 0) {
187 		dhcpmsg_init(argv[0], B_FALSE, is_verbose, debug_level);
188 		dhcpmsg(MSG_ERR, "cannot become daemon, exiting");
189 		dhcpmsg_fini();
190 		return (EXIT_FAILURE);
191 	}
192 
193 	/*
194 	 * Seed the random number generator, since we're going to need it
195 	 * to set transaction id's and for exponential backoff.
196 	 */
197 	srand48(gethrtime() ^ gethostid() ^ getpid());
198 
199 	dhcpmsg_init(argv[0], is_daemon, is_verbose, debug_level);
200 	(void) atexit(dhcpmsg_fini);
201 
202 	tq = iu_tq_create();
203 	eh = iu_eh_create();
204 
205 	if (eh == NULL || tq == NULL) {
206 		errno = ENOMEM;
207 		dhcpmsg(MSG_ERR, "cannot create timer queue or event handler");
208 		return (EXIT_FAILURE);
209 	}
210 
211 	/*
212 	 * ignore most signals that could be reasonably generated.
213 	 */
214 
215 	(void) signal(SIGTERM, graceful_shutdown);
216 	(void) signal(SIGQUIT, graceful_shutdown);
217 	(void) signal(SIGPIPE, SIG_IGN);
218 	(void) signal(SIGUSR1, SIG_IGN);
219 	(void) signal(SIGUSR2, SIG_IGN);
220 	(void) signal(SIGINT,  SIG_IGN);
221 	(void) signal(SIGHUP,  SIG_IGN);
222 	(void) signal(SIGCHLD, SIG_IGN);
223 
224 	/*
225 	 * upon SIGTHAW we need to refresh any non-infinite leases.
226 	 */
227 
228 	(void) iu_eh_register_signal(eh, SIGTHAW, refresh_smachs, NULL);
229 
230 	class_id = get_class_id();
231 	if (class_id != NULL)
232 		class_id_len = strlen(class_id);
233 	else
234 		dhcpmsg(MSG_WARNING, "get_class_id failed, continuing "
235 		    "with no vendor class id");
236 
237 	/*
238 	 * the inactivity timer is enabled any time there are no
239 	 * interfaces under DHCP control.  if DHCP_INACTIVITY_WAIT
240 	 * seconds transpire without an interface under DHCP control,
241 	 * the agent shuts down.
242 	 */
243 
244 	inactivity_id = iu_schedule_timer(tq, DHCP_INACTIVITY_WAIT,
245 	    inactivity_shutdown, NULL);
246 
247 	/*
248 	 * max out the number available descriptors, just in case..
249 	 */
250 
251 	rl.rlim_cur = RLIM_INFINITY;
252 	rl.rlim_max = RLIM_INFINITY;
253 	if (setrlimit(RLIMIT_NOFILE, &rl) == -1)
254 		dhcpmsg(MSG_ERR, "setrlimit failed");
255 
256 	(void) enable_extended_FILE_stdio(-1, -1);
257 
258 	/*
259 	 * Create and bind default IP sockets used to control interfaces and to
260 	 * catch stray packets.
261 	 */
262 
263 	if (!dhcp_ip_default())
264 		return (EXIT_FAILURE);
265 
266 	/*
267 	 * create the ipc channel that the agent will listen for
268 	 * requests on, and register it with the event handler so that
269 	 * `accept_event' will be called back.
270 	 */
271 
272 	switch (dhcp_ipc_init(&ipc_fd)) {
273 
274 	case 0:
275 		break;
276 
277 	case DHCP_IPC_E_BIND:
278 		dhcpmsg(MSG_ERROR, "dhcp_ipc_init: cannot bind to port "
279 		    "%i (agent already running?)", IPPORT_DHCPAGENT);
280 		return (EXIT_FAILURE);
281 
282 	default:
283 		dhcpmsg(MSG_ERROR, "dhcp_ipc_init failed");
284 		return (EXIT_FAILURE);
285 	}
286 
287 	if (iu_register_event(eh, ipc_fd, POLLIN, accept_event, 0) == -1) {
288 		dhcpmsg(MSG_ERR, "cannot register ipc fd for messages");
289 		return (EXIT_FAILURE);
290 	}
291 
292 	/*
293 	 * Create the global routing socket.  This is used for monitoring
294 	 * interface transitions, so that we learn about the kernel's Duplicate
295 	 * Address Detection status, and for inserting and removing default
296 	 * routes as learned from DHCP servers.  Both v4 and v6 are handed
297 	 * with this one socket.
298 	 */
299 	rtsock_fd = socket(PF_ROUTE, SOCK_RAW, 0);
300 	if (rtsock_fd == -1) {
301 		dhcpmsg(MSG_ERR, "cannot open routing socket");
302 		return (EXIT_FAILURE);
303 	}
304 	if (iu_register_event(eh, rtsock_fd, POLLIN, rtsock_event, 0) == -1) {
305 		dhcpmsg(MSG_ERR, "cannot register routing socket for messages");
306 		return (EXIT_FAILURE);
307 	}
308 
309 	/*
310 	 * if the -a (adopt) option was specified, try to adopt the
311 	 * kernel-managed interface before we start.
312 	 */
313 
314 	if (do_adopt && !dhcp_adopt())
315 		return (EXIT_FAILURE);
316 
317 	/*
318 	 * For DHCPv6, we own all of the interfaces marked DHCPRUNNING.  As
319 	 * we're starting operation here, if there are any of those interfaces
320 	 * lingering around, they're strays, and need to be removed.
321 	 *
322 	 * It might be nice to save these addresses off somewhere -- for both
323 	 * v4 and v6 -- and use them as hints for later negotiation.
324 	 */
325 	remove_v6_strays();
326 
327 	/*
328 	 * enter the main event loop; this is where all the real work
329 	 * takes place (through registering events and scheduling timers).
330 	 * this function only returns when the agent is shutting down.
331 	 */
332 
333 	switch (iu_handle_events(eh, tq)) {
334 
335 	case -1:
336 		dhcpmsg(MSG_WARNING, "iu_handle_events exited abnormally");
337 		break;
338 
339 	case DHCP_REASON_INACTIVITY:
340 		dhcpmsg(MSG_INFO, "no interfaces to manage, shutting down...");
341 		break;
342 
343 	case DHCP_REASON_TERMINATE:
344 		dhcpmsg(MSG_INFO, "received SIGTERM, shutting down...");
345 		break;
346 
347 	case DHCP_REASON_SIGNAL:
348 		dhcpmsg(MSG_WARNING, "received unexpected signal, shutting "
349 		    "down...");
350 		break;
351 	}
352 
353 	(void) iu_eh_unregister_signal(eh, SIGTHAW, NULL);
354 
355 	iu_eh_destroy(eh);
356 	iu_tq_destroy(tq);
357 
358 	return (EXIT_SUCCESS);
359 }
360 
361 /*
362  * drain_script(): event loop callback during shutdown
363  *
364  *   input: eh_t *: unused
365  *	    void *: unused
366  *  output: boolean_t: B_TRUE if event loop should exit; B_FALSE otherwise
367  */
368 
369 /* ARGSUSED */
370 boolean_t
371 drain_script(iu_eh_t *ehp, void *arg)
372 {
373 	if (shutdown_started == B_FALSE) {
374 		shutdown_started = B_TRUE;
375 		/*
376 		 * Check if the system is diskless client and/or
377 		 * there are active iSCSI sessions
378 		 *
379 		 * Do not drop the lease, or the system will be
380 		 * unable to sync(dump) through nfs/iSCSI driver
381 		 */
382 		if (!do_adopt && !is_iscsi_active()) {
383 			nuke_smach_list();
384 		}
385 	}
386 	return (script_count == 0);
387 }
388 
389 /*
390  * accept_event(): accepts a new connection on the ipc socket and registers
391  *		   to receive its messages with the event handler
392  *
393  *   input: iu_eh_t *: unused
394  *	    int: the file descriptor in the iu_eh_t * the connection came in on
395  *	    (other arguments unused)
396  *  output: void
397  */
398 
399 /* ARGSUSED */
400 static void
401 accept_event(iu_eh_t *ehp, int fd, short events, iu_event_id_t id, void *arg)
402 {
403 	int	client_fd;
404 	int	is_priv;
405 
406 	if (dhcp_ipc_accept(fd, &client_fd, &is_priv) != 0) {
407 		dhcpmsg(MSG_ERR, "accept_event: accept on ipc socket");
408 		return;
409 	}
410 
411 	if (iu_register_event(eh, client_fd, POLLIN, ipc_event,
412 	    (void *)is_priv) == -1) {
413 		dhcpmsg(MSG_ERROR, "accept_event: cannot register ipc socket "
414 		    "for callback");
415 	}
416 }
417 
418 /*
419  * ipc_event(): processes incoming ipc requests
420  *
421  *   input: iu_eh_t *: unused
422  *	    int: the file descriptor in the iu_eh_t * the request came in on
423  *	    short: unused
424  *	    iu_event_id_t: event ID
425  *	    void *: indicates whether the request is from a privileged client
426  *  output: void
427  */
428 
429 /* ARGSUSED */
430 static void
431 ipc_event(iu_eh_t *ehp, int fd, short events, iu_event_id_t id, void *arg)
432 {
433 	ipc_action_t		ia, *iap;
434 	dhcp_smach_t		*dsmp;
435 	int			error, is_priv = (int)arg;
436 	const char		*ifname;
437 	boolean_t		isv6;
438 
439 	ipc_action_init(&ia);
440 	error = dhcp_ipc_recv_request(fd, &ia.ia_request,
441 	    DHCP_IPC_REQUEST_WAIT);
442 	if (error != DHCP_IPC_SUCCESS) {
443 		if (error != DHCP_IPC_E_EOF) {
444 			dhcpmsg(MSG_ERROR,
445 			    "ipc_event: dhcp_ipc_recv_request failed: %s",
446 			    dhcp_ipc_strerror(error));
447 		} else {
448 			dhcpmsg(MSG_DEBUG, "ipc_event: connection closed");
449 		}
450 		if ((dsmp = lookup_smach_by_event(id)) != NULL) {
451 			ipc_action_finish(dsmp, error);
452 		} else {
453 			(void) iu_unregister_event(eh, id, NULL);
454 			(void) dhcp_ipc_close(fd);
455 		}
456 		return;
457 	}
458 
459 	/* Fill in temporary ipc_action structure for utility functions */
460 	ia.ia_cmd = DHCP_IPC_CMD(ia.ia_request->message_type);
461 	ia.ia_fd = fd;
462 	ia.ia_eid = id;
463 
464 	if (ia.ia_cmd >= DHCP_NIPC) {
465 		dhcpmsg(MSG_ERROR,
466 		    "ipc_event: invalid command (%s) attempted on %s",
467 		    dhcp_ipc_type_to_string(ia.ia_cmd), ia.ia_request->ifname);
468 		send_error_reply(&ia, DHCP_IPC_E_CMD_UNKNOWN);
469 		return;
470 	}
471 
472 	/* return EPERM for any of the privileged actions */
473 
474 	if (!is_priv && (ipc_cmd_flags[ia.ia_cmd] & CMD_ISPRIV)) {
475 		dhcpmsg(MSG_WARNING,
476 		    "ipc_event: privileged ipc command (%s) attempted on %s",
477 		    dhcp_ipc_type_to_string(ia.ia_cmd), ia.ia_request->ifname);
478 		send_error_reply(&ia, DHCP_IPC_E_PERM);
479 		return;
480 	}
481 
482 	/*
483 	 * Try to locate the state machine associated with this command.  If
484 	 * the command is DHCP_START or DHCP_INFORM and there isn't a state
485 	 * machine already, make one (there may already be one from a previous
486 	 * failed attempt to START or INFORM).  Otherwise, verify the reference
487 	 * is still valid.
488 	 *
489 	 * The interface name may be blank.  In that case, we look up the
490 	 * primary interface, and the requested type (v4 or v6) doesn't matter.
491 	 */
492 
493 	isv6 = (ia.ia_request->message_type & DHCP_V6) != 0;
494 	ifname = ia.ia_request->ifname;
495 	if (*ifname == '\0')
496 		dsmp = primary_smach(isv6);
497 	else
498 		dsmp = lookup_smach(ifname, isv6);
499 
500 	if (dsmp != NULL) {
501 		/* Note that verify_smach drops a reference */
502 		hold_smach(dsmp);
503 		if (!verify_smach(dsmp))
504 			dsmp = NULL;
505 	}
506 
507 	if (dsmp == NULL) {
508 		/*
509 		 * If the user asked for the primary DHCP interface, but there
510 		 * is none, then report failure.
511 		 */
512 		if (ifname[0] == '\0') {
513 			error = DHCP_IPC_E_NOPRIMARY;
514 
515 		/*
516 		 * If there's no interface, and we're starting up, then create
517 		 * it now, along with a state machine for it.  Note that if
518 		 * insert_smach fails, it discards the LIF reference.
519 		 */
520 		} else if (ipc_cmd_flags[ia.ia_cmd] & CMD_CREATE) {
521 			dhcp_lif_t *lif;
522 
523 			lif = attach_lif(ifname, isv6, &error);
524 			if (lif != NULL &&
525 			    (dsmp = insert_smach(lif, &error)) != NULL) {
526 				/*
527 				 * Get client ID and set "DHCPRUNNING" flag on
528 				 * logical interface.  (V4 only, because V6
529 				 * plumbs its own interfaces.)
530 				 */
531 				error = get_smach_cid(dsmp);
532 				if (error == DHCP_IPC_SUCCESS)
533 					error = set_lif_dhcp(lif, B_FALSE);
534 				if (error != DHCP_IPC_SUCCESS) {
535 					remove_smach(dsmp);
536 					dsmp = NULL;
537 				}
538 			}
539 
540 		/*
541 		 * Otherwise, this is an operation on an unknown interface.
542 		 */
543 		} else {
544 			error = DHCP_IPC_E_UNKIF;
545 		}
546 		if (dsmp == NULL) {
547 			send_error_reply(&ia, error);
548 			return;
549 		}
550 	}
551 
552 	if ((dsmp->dsm_dflags & DHCP_IF_BOOTP) &&
553 	    !(ipc_cmd_flags[ia.ia_cmd] & CMD_BOOTP)) {
554 		dhcpmsg(MSG_ERROR, "command %s not valid for BOOTP on %s",
555 		    dhcp_ipc_type_to_string(ia.ia_cmd), dsmp->dsm_name);
556 		send_error_reply(&ia, DHCP_IPC_E_BOOTP);
557 		return;
558 	}
559 
560 	/*
561 	 * verify that the state machine is in a state which will allow the
562 	 * command.  we do this up front so that we can return an error
563 	 * *before* needlessly cancelling an in-progress transaction.
564 	 */
565 
566 	if (!check_cmd_allowed(dsmp->dsm_state, ia.ia_cmd)) {
567 		dhcpmsg(MSG_DEBUG,
568 		    "in state %s; not allowing %s command on %s",
569 		    dhcp_state_to_string(dsmp->dsm_state),
570 		    dhcp_ipc_type_to_string(ia.ia_cmd), dsmp->dsm_name);
571 		send_error_reply(&ia,
572 		    ia.ia_cmd == DHCP_START && dsmp->dsm_state != INIT ?
573 		    DHCP_IPC_E_RUNNING : DHCP_IPC_E_OUTSTATE);
574 		return;
575 	}
576 
577 	dhcpmsg(MSG_DEBUG, "in state %s; allowing %s command on %s",
578 	    dhcp_state_to_string(dsmp->dsm_state),
579 	    dhcp_ipc_type_to_string(ia.ia_cmd), dsmp->dsm_name);
580 
581 	if ((ia.ia_request->message_type & DHCP_PRIMARY) && is_priv)
582 		make_primary(dsmp);
583 
584 	/*
585 	 * The current design dictates that there can be only one outstanding
586 	 * transaction per state machine -- this simplifies the code
587 	 * considerably and also fits well with RFCs 2131 and 3315.  It is
588 	 * worth classifying the different DHCP commands into synchronous
589 	 * (those which we will handle now and reply to immediately) and
590 	 * asynchronous (those which require transactions and will be completed
591 	 * at an indeterminate time in the future):
592 	 *
593 	 *    DROP: removes the agent's management of a state machine.
594 	 *	    asynchronous as the script program may be invoked.
595 	 *
596 	 *    PING: checks to see if the agent has a named state machine.
597 	 *	    synchronous, since no packets need to be sent
598 	 *	    to the DHCP server.
599 	 *
600 	 *  STATUS: returns information about a state machine.
601 	 *	    synchronous, since no packets need to be sent
602 	 *	    to the DHCP server.
603 	 *
604 	 * RELEASE: releases the agent's management of a state machine
605 	 *	    and brings the associated interfaces down.  asynchronous
606 	 *	    as the script program may be invoked.
607 	 *
608 	 *  EXTEND: renews a lease.  asynchronous, since the agent
609 	 *	    needs to wait for an ACK, etc.
610 	 *
611 	 *   START: starts DHCP on a named state machine.  asynchronous since
612 	 *	    the agent needs to wait for OFFERs, ACKs, etc.
613 	 *
614 	 *  INFORM: obtains configuration parameters for the system using
615 	 *	    externally configured interface.  asynchronous, since the
616 	 *	    agent needs to wait for an ACK.
617 	 *
618 	 * Notice that EXTEND, INFORM, START, DROP and RELEASE are
619 	 * asynchronous.  Notice also that asynchronous commands may occur from
620 	 * within the agent -- for instance, the agent will need to do implicit
621 	 * EXTENDs to extend the lease. In order to make the code simpler, the
622 	 * following rules apply for asynchronous commands:
623 	 *
624 	 * There can only be one asynchronous command at a time per state
625 	 * machine.  The current asynchronous command is managed by the async_*
626 	 * api: async_start(), async_finish(), and async_cancel().
627 	 * async_start() starts management of a new asynchronous command on an
628 	 * state machine, which should only be done after async_cancel() to
629 	 * terminate a previous command.  When the command is completed,
630 	 * async_finish() should be called.
631 	 *
632 	 * Asynchronous commands started by a user command have an associated
633 	 * ipc_action which provides the agent with information for how to get
634 	 * in touch with the user command when the action completes.  These
635 	 * ipc_action records also have an associated timeout which may be
636 	 * infinite.  ipc_action_start() should be called when starting an
637 	 * asynchronous command requested by a user, which sets up the timer
638 	 * and keeps track of the ipc information (file descriptor, request
639 	 * type).  When the asynchronous command completes, ipc_action_finish()
640 	 * should be called to return a command status code to the user and
641 	 * close the ipc connection).  If the command does not complete before
642 	 * the timer fires, ipc_action_timeout() is called which closes the ipc
643 	 * connection and returns DHCP_IPC_E_TIMEOUT to the user.  Note that
644 	 * independent of ipc_action_timeout(), ipc_action_finish() should be
645 	 * called.
646 	 *
647 	 * on a case-by-case basis, here is what happens (per state machine):
648 	 *
649 	 *    o When an asynchronous command is requested, then
650 	 *	async_cancel() is called to terminate any non-user
651 	 *	action in progress.  If there's a user action running,
652 	 *	the user command is sent DHCP_IPC_E_PEND.
653 	 *
654 	 *    o otherwise, the the transaction is started with
655 	 *	async_start().  if the transaction is on behalf
656 	 *	of a user, ipc_action_start() is called to keep
657 	 *	track of the ipc information and set up the
658 	 *	ipc_action timer.
659 	 *
660 	 *    o if the command completes normally and before a
661 	 *	timeout fires, then async_finish() is called.
662 	 *	if there was an associated ipc_action,
663 	 *	ipc_action_finish() is called to complete it.
664 	 *
665 	 *    o if the command fails before a timeout fires, then
666 	 *	async_finish() is called, and the state machine is
667 	 *	is returned to a known state based on the command.
668 	 *	if there was an associated ipc_action,
669 	 *	ipc_action_finish() is called to complete it.
670 	 *
671 	 *    o if the ipc_action timer fires before command
672 	 *	completion, then DHCP_IPC_E_TIMEOUT is returned to
673 	 *	the user.  however, the transaction continues to
674 	 *	be carried out asynchronously.
675 	 */
676 
677 	if (ipc_cmd_flags[ia.ia_cmd] & CMD_IMMED) {
678 		/*
679 		 * Only immediate commands (ping, status, get_tag) need to
680 		 * worry about freeing ia through one of the reply functions
681 		 * before returning.
682 		 */
683 		iap = &ia;
684 	} else {
685 		/*
686 		 * if shutdown request has been received, send back an error.
687 		 */
688 		if (shutdown_started) {
689 			send_error_reply(&ia, DHCP_IPC_E_OUTSTATE);
690 			return;
691 		}
692 
693 		if (dsmp->dsm_dflags & DHCP_IF_BUSY) {
694 			send_error_reply(&ia, DHCP_IPC_E_PEND);
695 			return;
696 		}
697 
698 		if (!ipc_action_start(dsmp, &ia)) {
699 			dhcpmsg(MSG_WARNING, "ipc_event: ipc_action_start "
700 			    "failed for %s", dsmp->dsm_name);
701 			send_error_reply(&ia, DHCP_IPC_E_MEMORY);
702 			return;
703 		}
704 
705 		/* Action structure consumed by above function */
706 		iap = &dsmp->dsm_ia;
707 	}
708 
709 	switch (iap->ia_cmd) {
710 
711 	case DHCP_DROP:
712 		if (dsmp->dsm_droprelease)
713 			break;
714 		dsmp->dsm_droprelease = B_TRUE;
715 		(void) script_start(dsmp, isv6 ? EVENT_DROP6 : EVENT_DROP,
716 		    dhcp_drop, NULL, NULL);
717 		break;		/* not an immediate function */
718 
719 	case DHCP_EXTEND:
720 		(void) dhcp_extending(dsmp);
721 		break;
722 
723 	case DHCP_GET_TAG: {
724 		dhcp_optnum_t	optnum;
725 		void		*opt = NULL;
726 		uint_t		optlen;
727 		boolean_t	did_alloc = B_FALSE;
728 		PKT_LIST	*ack = dsmp->dsm_ack;
729 
730 		/*
731 		 * verify the request makes sense.
732 		 */
733 
734 		if (iap->ia_request->data_type   != DHCP_TYPE_OPTNUM ||
735 		    iap->ia_request->data_length != sizeof (dhcp_optnum_t)) {
736 			send_error_reply(iap, DHCP_IPC_E_PROTO);
737 			break;
738 		}
739 
740 		(void) memcpy(&optnum, iap->ia_request->buffer,
741 		    sizeof (dhcp_optnum_t));
742 
743 load_option:
744 		switch (optnum.category) {
745 
746 		case DSYM_SITE:			/* FALLTHRU */
747 		case DSYM_STANDARD:
748 			if (isv6) {
749 				opt = dhcpv6_pkt_option(ack, NULL, optnum.code,
750 				    NULL);
751 			} else {
752 				if (optnum.code <= DHCP_LAST_OPT)
753 					opt = ack->opts[optnum.code];
754 			}
755 			break;
756 
757 		case DSYM_VENDOR:
758 			if (isv6) {
759 				dhcpv6_option_t *d6o;
760 				uint32_t ent;
761 
762 				/*
763 				 * Look through vendor options to find our
764 				 * enterprise number.
765 				 */
766 				d6o = NULL;
767 				for (;;) {
768 					d6o = dhcpv6_pkt_option(ack, d6o,
769 					    DHCPV6_OPT_VENDOR_OPT, &optlen);
770 					if (d6o == NULL)
771 						break;
772 					optlen -= sizeof (*d6o);
773 					if (optlen < sizeof (ent))
774 						continue;
775 					(void) memcpy(&ent, d6o + 1,
776 					    sizeof (ent));
777 					if (ntohl(ent) != DHCPV6_SUN_ENT)
778 						continue;
779 					break;
780 				}
781 				if (d6o != NULL) {
782 					/*
783 					 * Now find the requested vendor option
784 					 * within the vendor options block.
785 					 */
786 					opt = dhcpv6_find_option(
787 					    (char *)(d6o + 1) + sizeof (ent),
788 					    optlen - sizeof (ent), NULL,
789 					    optnum.code, NULL);
790 				}
791 			} else {
792 				/*
793 				 * the test against VS_OPTION_START is broken
794 				 * up into two tests to avoid compiler warnings
795 				 * under intel.
796 				 */
797 				if ((optnum.code > VS_OPTION_START ||
798 				    optnum.code == VS_OPTION_START) &&
799 				    optnum.code <= VS_OPTION_END)
800 					opt = ack->vs[optnum.code];
801 			}
802 			break;
803 
804 		case DSYM_FIELD:
805 			if (isv6) {
806 				dhcpv6_message_t *d6m =
807 				    (dhcpv6_message_t *)ack->pkt;
808 				dhcpv6_option_t *d6o;
809 
810 				/* Validate the packet field the user wants */
811 				optlen = optnum.code + optnum.size;
812 				if (d6m->d6m_msg_type ==
813 				    DHCPV6_MSG_RELAY_FORW ||
814 				    d6m->d6m_msg_type ==
815 				    DHCPV6_MSG_RELAY_REPL) {
816 					if (optlen > sizeof (dhcpv6_relay_t))
817 						break;
818 				} else {
819 					if (optlen > sizeof (*d6m))
820 						break;
821 				}
822 
823 				opt = malloc(sizeof (*d6o) + optnum.size);
824 				if (opt != NULL) {
825 					d6o = opt;
826 					d6o->d6o_code = htons(optnum.code);
827 					d6o->d6o_len = htons(optnum.size);
828 					(void) memcpy(d6o + 1, (caddr_t)d6m +
829 					    optnum.code, optnum.size);
830 				}
831 			} else {
832 				if (optnum.code + optnum.size > sizeof (PKT))
833 					break;
834 
835 				/*
836 				 * + 2 to account for option code and length
837 				 * byte
838 				 */
839 				opt = malloc(optnum.size + 2);
840 				if (opt != NULL) {
841 					DHCP_OPT *v4opt = opt;
842 
843 					v4opt->len  = optnum.size;
844 					v4opt->code = optnum.code;
845 					(void) memcpy(v4opt->value,
846 					    (caddr_t)ack->pkt + optnum.code,
847 					    optnum.size);
848 				}
849 			}
850 
851 			if (opt == NULL) {
852 				send_error_reply(iap, DHCP_IPC_E_MEMORY);
853 				return;
854 			}
855 			did_alloc = B_TRUE;
856 			break;
857 
858 		default:
859 			send_error_reply(iap, DHCP_IPC_E_PROTO);
860 			return;
861 		}
862 
863 		/*
864 		 * return the option payload, if there was one.  the "+ 2"
865 		 * accounts for the option code number and length byte.
866 		 */
867 
868 		if (opt != NULL) {
869 			if (isv6) {
870 				dhcpv6_option_t d6ov;
871 
872 				(void) memcpy(&d6ov, opt, sizeof (d6ov));
873 				optlen = ntohs(d6ov.d6o_len) + sizeof (d6ov);
874 			} else {
875 				optlen = ((DHCP_OPT *)opt)->len + 2;
876 			}
877 			send_data_reply(iap, 0, DHCP_TYPE_OPTION, opt, optlen);
878 
879 			if (did_alloc)
880 				free(opt);
881 			break;
882 		} else if (ack != dsmp->dsm_orig_ack) {
883 			/*
884 			 * There wasn't any definition for the option in the
885 			 * current ack, so now retry with the original ack if
886 			 * the original ack is not the current ack.
887 			 */
888 			ack = dsmp->dsm_orig_ack;
889 			goto load_option;
890 		}
891 
892 		/*
893 		 * note that an "okay" response is returned either in
894 		 * the case of an unknown option or a known option
895 		 * with no payload.  this is okay (for now) since
896 		 * dhcpinfo checks whether an option is valid before
897 		 * ever performing ipc with the agent.
898 		 */
899 
900 		send_ok_reply(iap);
901 		break;
902 	}
903 
904 	case DHCP_INFORM:
905 		dhcp_inform(dsmp);
906 		/* next destination: dhcp_acknak() */
907 		break;		/* not an immediate function */
908 
909 	case DHCP_PING:
910 		if (dsmp->dsm_dflags & DHCP_IF_FAILED)
911 			send_error_reply(iap, DHCP_IPC_E_FAILEDIF);
912 		else
913 			send_ok_reply(iap);
914 		break;
915 
916 	case DHCP_RELEASE:
917 		if (dsmp->dsm_droprelease)
918 			break;
919 		dsmp->dsm_droprelease = B_TRUE;
920 		(void) script_start(dsmp, isv6 ? EVENT_RELEASE6 :
921 		    EVENT_RELEASE, dhcp_release, "Finished with lease.", NULL);
922 		break;		/* not an immediate function */
923 
924 	case DHCP_START: {
925 		PKT_LIST *ack, *oack;
926 		PKT_LIST *plp[2];
927 
928 		deprecate_leases(dsmp);
929 
930 		/*
931 		 * if we have a valid hostconf lying around, then jump
932 		 * into INIT_REBOOT.  if it fails, we'll end up going
933 		 * through the whole selecting() procedure again.
934 		 */
935 
936 		error = read_hostconf(dsmp->dsm_name, plp, 2, dsmp->dsm_isv6);
937 		ack = error > 0 ? plp[0] : NULL;
938 		oack = error > 1 ? plp[1] : NULL;
939 
940 		/*
941 		 * If the allocation of the old ack fails, that's fine;
942 		 * continue without it.
943 		 */
944 		if (oack == NULL)
945 			oack = ack;
946 
947 		/*
948 		 * As long as we've allocated something, start using it.
949 		 */
950 		if (ack != NULL) {
951 			dsmp->dsm_orig_ack = oack;
952 			dsmp->dsm_ack = ack;
953 			dhcp_init_reboot(dsmp);
954 			/* next destination: dhcp_acknak() */
955 			break;
956 		}
957 
958 		/*
959 		 * if not debugging, wait for a few seconds before
960 		 * going into SELECTING.
961 		 */
962 
963 		if (debug_level == 0 && set_start_timer(dsmp)) {
964 			/* next destination: dhcp_start() */
965 			break;
966 		} else {
967 			dhcp_selecting(dsmp);
968 			/* next destination: dhcp_requesting() */
969 			break;
970 		}
971 	}
972 
973 	case DHCP_STATUS: {
974 		dhcp_status_t	status;
975 		dhcp_lease_t	*dlp;
976 
977 		status.if_began = monosec_to_time(dsmp->dsm_curstart_monosec);
978 
979 		/*
980 		 * We return information on just the first lease as being
981 		 * representative of the lot.  A better status mechanism is
982 		 * needed.
983 		 */
984 		dlp = dsmp->dsm_leases;
985 
986 		if (dlp == NULL ||
987 		    dlp->dl_lifs->lif_expire.dt_start == DHCP_PERM) {
988 			status.if_t1	= DHCP_PERM;
989 			status.if_t2	= DHCP_PERM;
990 			status.if_lease	= DHCP_PERM;
991 		} else {
992 			status.if_t1	= status.if_began +
993 			    dlp->dl_t1.dt_start;
994 			status.if_t2	= status.if_began +
995 			    dlp->dl_t2.dt_start;
996 			status.if_lease	= status.if_began +
997 			    dlp->dl_lifs->lif_expire.dt_start;
998 		}
999 
1000 		status.version		= DHCP_STATUS_VER;
1001 		status.if_state		= dsmp->dsm_state;
1002 		status.if_dflags	= dsmp->dsm_dflags;
1003 		status.if_sent		= dsmp->dsm_sent;
1004 		status.if_recv		= dsmp->dsm_received;
1005 		status.if_bad_offers	= dsmp->dsm_bad_offers;
1006 
1007 		(void) strlcpy(status.if_name, dsmp->dsm_name, IFNAMSIZ);
1008 
1009 		send_data_reply(iap, 0, DHCP_TYPE_STATUS, &status,
1010 		    sizeof (dhcp_status_t));
1011 		break;
1012 	}
1013 	}
1014 }
1015 
1016 /*
1017  * check_rtm_addr(): determine if routing socket message matches interface
1018  *		     address
1019  *
1020  *   input: const struct if_msghdr *: pointer to routing socket message
1021  *	    int: routing socket message length
1022  *	    boolean_t: set to B_TRUE if IPv6
1023  *	    const in6_addr_t *: pointer to IP address
1024  *  output: boolean_t: B_TRUE if address is a match
1025  */
1026 
1027 static boolean_t
1028 check_rtm_addr(const struct ifa_msghdr *ifam, int msglen, boolean_t isv6,
1029     const in6_addr_t *addr)
1030 {
1031 	const char *cp, *lim;
1032 	uint_t flag;
1033 	const struct sockaddr *sa;
1034 
1035 	if (!(ifam->ifam_addrs & RTA_IFA))
1036 		return (B_FALSE);
1037 
1038 	cp = (const char *)(ifam + 1);
1039 	lim = (const char *)ifam + msglen;
1040 	for (flag = 1; flag < RTA_IFA; flag <<= 1) {
1041 		if (ifam->ifam_addrs & flag) {
1042 			/* LINTED: alignment */
1043 			sa = (const struct sockaddr *)cp;
1044 			if ((const char *)(sa + 1) > lim)
1045 				return (B_FALSE);
1046 			switch (sa->sa_family) {
1047 			case AF_INET:
1048 				cp += sizeof (struct sockaddr_in);
1049 				break;
1050 			case AF_LINK:
1051 				cp += sizeof (struct sockaddr_dl);
1052 				break;
1053 			case AF_INET6:
1054 				cp += sizeof (struct sockaddr_in6);
1055 				break;
1056 			default:
1057 				cp += sizeof (struct sockaddr);
1058 				break;
1059 			}
1060 		}
1061 	}
1062 	if (isv6) {
1063 		const struct sockaddr_in6 *sin6;
1064 
1065 		/* LINTED: alignment */
1066 		sin6 = (const struct sockaddr_in6 *)cp;
1067 		if ((const char *)(sin6 + 1) > lim)
1068 			return (B_FALSE);
1069 		if (sin6->sin6_family != AF_INET6)
1070 			return (B_FALSE);
1071 		return (IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr, addr));
1072 	} else {
1073 		const struct sockaddr_in *sinp;
1074 		ipaddr_t v4addr;
1075 
1076 		/* LINTED: alignment */
1077 		sinp = (const struct sockaddr_in *)cp;
1078 		if ((const char *)(sinp + 1) > lim)
1079 			return (B_FALSE);
1080 		if (sinp->sin_family != AF_INET)
1081 			return (B_FALSE);
1082 		IN6_V4MAPPED_TO_IPADDR(addr, v4addr);
1083 		return (sinp->sin_addr.s_addr == v4addr);
1084 	}
1085 }
1086 
1087 /*
1088  * is_rtm_v6(): determine if routing socket message is IPv6
1089  *
1090  *   input: struct ifa_msghdr *: pointer to routing socket message
1091  *	    int: message length
1092  *  output: boolean_t
1093  */
1094 
1095 static boolean_t
1096 is_rtm_v6(const struct ifa_msghdr *ifam, int msglen)
1097 {
1098 	const char *cp, *lim;
1099 	uint_t flag;
1100 	const struct sockaddr *sa;
1101 
1102 	cp = (const char *)(ifam + 1);
1103 	lim = (const char *)ifam + msglen;
1104 	for (flag = ifam->ifam_addrs; flag != 0; flag &= flag - 1) {
1105 		/* LINTED: alignment */
1106 		sa = (const struct sockaddr *)cp;
1107 		if ((const char *)(sa + 1) > lim)
1108 			return (B_FALSE);
1109 		switch (sa->sa_family) {
1110 		case AF_INET:
1111 			return (B_FALSE);
1112 		case AF_LINK:
1113 			cp += sizeof (struct sockaddr_dl);
1114 			break;
1115 		case AF_INET6:
1116 			return (B_TRUE);
1117 		default:
1118 			cp += sizeof (struct sockaddr);
1119 			break;
1120 		}
1121 	}
1122 	return (B_FALSE);
1123 }
1124 
1125 /*
1126  * check_lif(): check the state of a given logical interface and its DHCP
1127  *		lease.  We've been told by the routing socket that the
1128  *		corresponding ifIndex has changed.  This may mean that DAD has
1129  *		completed or failed.
1130  *
1131  *   input: dhcp_lif_t *: pointer to the LIF
1132  *	    const struct ifa_msghdr *: routing socket message
1133  *	    int: size of routing socket message
1134  *  output: boolean_t: B_TRUE if DAD has completed on this interface
1135  */
1136 
1137 static boolean_t
1138 check_lif(dhcp_lif_t *lif, const struct ifa_msghdr *ifam, int msglen)
1139 {
1140 	boolean_t isv6, dad_wait, unplumb;
1141 	int fd;
1142 	struct lifreq lifr;
1143 
1144 	isv6 = lif->lif_pif->pif_isv6;
1145 	fd = isv6 ? v6_sock_fd : v4_sock_fd;
1146 
1147 	/*
1148 	 * Get the real (64 bit) logical interface flags.  Note that the
1149 	 * routing socket message has flags, but these are just the lower 32
1150 	 * bits.
1151 	 */
1152 	unplumb = B_FALSE;
1153 	(void) memset(&lifr, 0, sizeof (lifr));
1154 	(void) strlcpy(lifr.lifr_name, lif->lif_name, sizeof (lifr.lifr_name));
1155 	if (ioctl(fd, SIOCGLIFFLAGS, &lifr) == -1) {
1156 		/*
1157 		 * Failing to retrieve flags means that the interface is gone.
1158 		 * It hasn't failed to verify with DAD, but we still have to
1159 		 * give up on it.
1160 		 */
1161 		lifr.lifr_flags = 0;
1162 		if (errno == ENXIO) {
1163 			lif->lif_plumbed = B_FALSE;
1164 			dhcpmsg(MSG_INFO, "%s has been removed; abandoning",
1165 			    lif->lif_name);
1166 			if (!isv6)
1167 				discard_default_routes(lif->lif_smachs);
1168 		} else {
1169 			dhcpmsg(MSG_ERR,
1170 			    "unable to retrieve interface flags on %s",
1171 			    lif->lif_name);
1172 		}
1173 		unplumb = B_TRUE;
1174 	} else if (!check_rtm_addr(ifam, msglen, isv6, &lif->lif_v6addr)) {
1175 		/*
1176 		 * If the message is not about this logical interface,
1177 		 * then just ignore it.
1178 		 */
1179 		return (B_FALSE);
1180 	} else if (lifr.lifr_flags & IFF_DUPLICATE) {
1181 		dhcpmsg(MSG_ERROR, "interface %s has duplicate address",
1182 		    lif->lif_name);
1183 		lif_mark_decline(lif, "duplicate address");
1184 		close_ip_lif(lif);
1185 		(void) open_ip_lif(lif, INADDR_ANY);
1186 	}
1187 
1188 	dad_wait = lif->lif_dad_wait;
1189 	if (dad_wait) {
1190 		dhcpmsg(MSG_VERBOSE, "check_lif: %s has finished DAD",
1191 		    lif->lif_name);
1192 		lif->lif_dad_wait = B_FALSE;
1193 	}
1194 
1195 	if (unplumb)
1196 		unplumb_lif(lif);
1197 
1198 	return (dad_wait);
1199 }
1200 
1201 /*
1202  * check_main_lif(): check the state of a main logical interface for a state
1203  *		     machine.  This is used only for DHCPv6.
1204  *
1205  *   input: dhcp_smach_t *: pointer to the state machine
1206  *	    const struct ifa_msghdr *: routing socket message
1207  *	    int: size of routing socket message
1208  *  output: boolean_t: B_TRUE if LIF is ok.
1209  */
1210 
1211 static boolean_t
1212 check_main_lif(dhcp_smach_t *dsmp, const struct ifa_msghdr *ifam, int msglen)
1213 {
1214 	dhcp_lif_t *lif = dsmp->dsm_lif;
1215 	struct lifreq lifr;
1216 
1217 	/*
1218 	 * Get the real (64 bit) logical interface flags.  Note that the
1219 	 * routing socket message has flags, but these are just the lower 32
1220 	 * bits.
1221 	 */
1222 	(void) memset(&lifr, 0, sizeof (lifr));
1223 	(void) strlcpy(lifr.lifr_name, lif->lif_name, sizeof (lifr.lifr_name));
1224 	if (ioctl(v6_sock_fd, SIOCGLIFFLAGS, &lifr) == -1) {
1225 		/*
1226 		 * Failing to retrieve flags means that the interface is gone.
1227 		 * Our state machine is now trash.
1228 		 */
1229 		if (errno == ENXIO) {
1230 			dhcpmsg(MSG_INFO, "%s has been removed; abandoning",
1231 			    lif->lif_name);
1232 		} else {
1233 			dhcpmsg(MSG_ERR,
1234 			    "unable to retrieve interface flags on %s",
1235 			    lif->lif_name);
1236 		}
1237 		return (B_FALSE);
1238 	} else if (!check_rtm_addr(ifam, msglen, B_TRUE, &lif->lif_v6addr)) {
1239 		/*
1240 		 * If the message is not about this logical interface,
1241 		 * then just ignore it.
1242 		 */
1243 		return (B_TRUE);
1244 	} else if (lifr.lifr_flags & IFF_DUPLICATE) {
1245 		dhcpmsg(MSG_ERROR, "interface %s has duplicate address",
1246 		    lif->lif_name);
1247 		return (B_FALSE);
1248 	} else {
1249 		return (B_TRUE);
1250 	}
1251 }
1252 
1253 /*
1254  * process_link_up_down(): check the state of a physical interface for up/down
1255  *			   transitions; must go through INIT_REBOOT state if
1256  *			   the link flaps.
1257  *
1258  *   input: dhcp_pif_t *: pointer to the physical interface to check
1259  *	    const struct if_msghdr *: routing socket message
1260  *  output: none
1261  */
1262 
1263 static void
1264 process_link_up_down(dhcp_pif_t *pif, const struct if_msghdr *ifm)
1265 {
1266 	struct lifreq lifr;
1267 	boolean_t isv6;
1268 	int fd;
1269 
1270 	/*
1271 	 * If the message implies no change of flags, then we're done; no need
1272 	 * to check further.  Note that if we have multiple state machines on a
1273 	 * single physical interface, this test keeps us from issuing an ioctl
1274 	 * for each one.
1275 	 */
1276 	if ((ifm->ifm_flags & IFF_RUNNING) && pif->pif_running ||
1277 	    !(ifm->ifm_flags & IFF_RUNNING) && !pif->pif_running)
1278 		return;
1279 
1280 	/*
1281 	 * We don't know what the real interface flags are, because the
1282 	 * if_index number is only 16 bits; we must go ask.
1283 	 */
1284 	isv6 = pif->pif_isv6;
1285 	fd = isv6 ? v6_sock_fd : v4_sock_fd;
1286 	(void) memset(&lifr, 0, sizeof (lifr));
1287 	(void) strlcpy(lifr.lifr_name, pif->pif_name, sizeof (lifr.lifr_name));
1288 
1289 	if (ioctl(fd, SIOCGLIFFLAGS, &lifr) == -1 ||
1290 	    !(lifr.lifr_flags & IFF_RUNNING)) {
1291 		/*
1292 		 * If we've lost the interface or it has gone down, then
1293 		 * nothing special to do; just turn off the running flag.
1294 		 */
1295 		pif_status(pif, B_FALSE);
1296 	} else {
1297 		/*
1298 		 * Interface has come back up: go through verification process.
1299 		 */
1300 		pif_status(pif, B_TRUE);
1301 	}
1302 }
1303 
1304 /*
1305  * rtsock_event(): fetches routing socket messages and updates internal
1306  *		   interface state based on those messages.
1307  *
1308  *   input: iu_eh_t *: unused
1309  *	    int: the routing socket file descriptor
1310  *	    (other arguments unused)
1311  *  output: void
1312  */
1313 
1314 /* ARGSUSED */
1315 static void
1316 rtsock_event(iu_eh_t *ehp, int fd, short events, iu_event_id_t id, void *arg)
1317 {
1318 	dhcp_smach_t *dsmp, *dsmnext;
1319 	union {
1320 		struct ifa_msghdr ifam;
1321 		struct if_msghdr ifm;
1322 		char buf[1024];
1323 	} msg;
1324 	uint16_t ifindex;
1325 	int msglen;
1326 	boolean_t isv6;
1327 
1328 	if ((msglen = read(fd, &msg, sizeof (msg))) <= 0)
1329 		return;
1330 
1331 	/* Note that the routing socket interface index is just 16 bits */
1332 	if (msg.ifm.ifm_type == RTM_IFINFO) {
1333 		ifindex = msg.ifm.ifm_index;
1334 		isv6 = (msg.ifm.ifm_flags & IFF_IPV6) ? B_TRUE : B_FALSE;
1335 	} else if (msg.ifam.ifam_type == RTM_DELADDR ||
1336 	    msg.ifam.ifam_type == RTM_NEWADDR) {
1337 		ifindex = msg.ifam.ifam_index;
1338 		isv6 = is_rtm_v6(&msg.ifam, msglen);
1339 	} else {
1340 		return;
1341 	}
1342 
1343 	for (dsmp = lookup_smach_by_uindex(ifindex, NULL, isv6);
1344 	    dsmp != NULL; dsmp = dsmnext) {
1345 		DHCPSTATE oldstate;
1346 		boolean_t lif_finished;
1347 		boolean_t lease_removed;
1348 		dhcp_lease_t *dlp, *dlnext;
1349 
1350 		/*
1351 		 * Note that script_start can call dhcp_drop directly, and
1352 		 * that will do release_smach.
1353 		 */
1354 		dsmnext = lookup_smach_by_uindex(ifindex, dsmp, isv6);
1355 		oldstate = dsmp->dsm_state;
1356 
1357 		/*
1358 		 * Ignore state machines that are currently processing drop or
1359 		 * release; there is nothing more we can do for them.
1360 		 */
1361 		if (dsmp->dsm_droprelease)
1362 			continue;
1363 
1364 		/*
1365 		 * Look for link up/down notifications.  These occur on a
1366 		 * physical interface basis.
1367 		 */
1368 		if (msg.ifm.ifm_type == RTM_IFINFO) {
1369 			process_link_up_down(dsmp->dsm_lif->lif_pif, &msg.ifm);
1370 			continue;
1371 		}
1372 
1373 		/*
1374 		 * Since we cannot trust the flags reported by the routing
1375 		 * socket (they're just 32 bits -- and thus never include
1376 		 * IFF_DUPLICATE), and we can't trust the ifindex (it's only 16
1377 		 * bits and also doesn't reflect the alias in use), we get
1378 		 * flags on all matching interfaces, and go by that.
1379 		 */
1380 		lif_finished = B_FALSE;
1381 		lease_removed = B_FALSE;
1382 		for (dlp = dsmp->dsm_leases; dlp != NULL; dlp = dlnext) {
1383 			dhcp_lif_t *lif, *lifnext;
1384 			uint_t nlifs = dlp->dl_nlifs;
1385 
1386 			dlnext = dlp->dl_next;
1387 			for (lif = dlp->dl_lifs; lif != NULL && nlifs > 0;
1388 			    lif = lifnext, nlifs--) {
1389 				lifnext = lif->lif_next;
1390 				if (check_lif(lif, &msg.ifam, msglen)) {
1391 					dsmp->dsm_lif_wait--;
1392 					lif_finished = B_TRUE;
1393 				}
1394 			}
1395 			if (dlp->dl_nlifs == 0) {
1396 				remove_lease(dlp);
1397 				lease_removed = B_TRUE;
1398 			}
1399 		}
1400 
1401 		if ((isv6 && !check_main_lif(dsmp, &msg.ifam, msglen)) ||
1402 		    (!isv6 && !verify_lif(dsmp->dsm_lif))) {
1403 			if (dsmp->dsm_script_pid != -1)
1404 				script_stop(dsmp);
1405 			dsmp->dsm_droprelease = B_TRUE;
1406 			(void) script_start(dsmp, isv6 ? EVENT_DROP6 :
1407 			    EVENT_DROP, dhcp_drop, NULL, NULL);
1408 			continue;
1409 		}
1410 
1411 		/*
1412 		 * Ignore this state machine if nothing interesting has
1413 		 * happened.
1414 		 */
1415 		if (!lif_finished && dsmp->dsm_lif_down == 0 &&
1416 		    (dsmp->dsm_leases != NULL || !lease_removed))
1417 			continue;
1418 
1419 		/*
1420 		 * If we're still waiting for DAD to complete on some of the
1421 		 * configured LIFs, then don't send a response.
1422 		 */
1423 		if (dsmp->dsm_lif_wait != 0) {
1424 			dhcpmsg(MSG_VERBOSE, "rtsock_event: %s still has %d "
1425 			    "LIFs waiting on DAD", dsmp->dsm_name,
1426 			    dsmp->dsm_lif_wait);
1427 			continue;
1428 		}
1429 
1430 		/*
1431 		 * If we have some failed LIFs, then handle them now.  We'll
1432 		 * remove them from the list.  Any leases that become empty are
1433 		 * also removed as part of the decline-generation process.
1434 		 */
1435 		if (dsmp->dsm_lif_down != 0)
1436 			send_declines(dsmp);
1437 
1438 		if (dsmp->dsm_leases == NULL) {
1439 			dsmp->dsm_bad_offers++;
1440 			/*
1441 			 * For DHCPv6, we'll process the restart once we're
1442 			 * done sending Decline messages, because these are
1443 			 * supposed to be acknowledged.  With DHCPv4, there's
1444 			 * no acknowledgment for a DECLINE, so after sending
1445 			 * it, we just restart right away.
1446 			 */
1447 			if (!dsmp->dsm_isv6) {
1448 				dhcpmsg(MSG_VERBOSE, "rtsock_event: %s has no "
1449 				    "LIFs left", dsmp->dsm_name);
1450 				dhcp_restart(dsmp);
1451 			}
1452 		} else {
1453 			/*
1454 			 * If we're now up on at least some of the leases and
1455 			 * we were waiting for that, then kick off the rest of
1456 			 * configuration.  Lease validation and DAD are done.
1457 			 */
1458 			dhcpmsg(MSG_VERBOSE, "rtsock_event: all LIFs verified "
1459 			    "on %s in %s state", dsmp->dsm_name,
1460 			    dhcp_state_to_string(oldstate));
1461 			if (oldstate == PRE_BOUND ||
1462 			    oldstate == ADOPTING)
1463 				dhcp_bound_complete(dsmp);
1464 			if (oldstate == ADOPTING)
1465 				dhcp_adopt_complete(dsmp);
1466 		}
1467 	}
1468 }
1469 
1470 /*
1471  * check_cmd_allowed(): check whether the requested command is allowed in the
1472  *			state specified.
1473  *
1474  *   input: DHCPSTATE: current state
1475  *	    dhcp_ipc_type_t: requested command
1476  *  output: boolean_t: B_TRUE if command is allowed in this state
1477  */
1478 
1479 boolean_t
1480 check_cmd_allowed(DHCPSTATE state, dhcp_ipc_type_t cmd)
1481 {
1482 	return (ipc_cmd_allowed[state][cmd] != 0);
1483 }
1484 
1485 static boolean_t
1486 is_iscsi_active(void)
1487 {
1488 	int	fd;
1489 	int	active;
1490 
1491 	if ((fd = open(ISCSI_DRIVER_DEVCTL, O_RDONLY)) == -1) {
1492 		return (B_FALSE);
1493 	}
1494 
1495 	if ((ioctl(fd, ISCSI_IS_ACTIVE, &active)) != 0) {
1496 		active = 0;
1497 	}
1498 	(void) close(fd);
1499 	if (active) {
1500 		return (B_TRUE);
1501 	} else {
1502 		return (B_FALSE);
1503 	}
1504 }
1505